Cairo - Egypt will lower its customs exchange rate to 16.25 pounds per dollar from 16.50, effective from Tuesday August 1st, Finance Minister Amr El-Garhy told Reuters on Sunday. The new rate will be set for one month, he said, in what is the first such drop in four months. Egypt began setting a monthly fixed customs exchange rate in January following the flotation of its pound currency in November. It has since set it each month.